Machine for making containers by blow-moulding plastic parisons

Details Machine for making containers by blow-moulding plastic parisons Machine for making containers by blow-moulding plastic parisons

1997-09-02

1999-01-26

Davis, Robert

Plastic article or earthenware shaping or treating: apparatus

Female mold and means to shape parison directly by internal...

With heating or cooling means

264538, 425534, B29C 3108, B29C 4964

Patent

active

058635718

DESCRIPTION:

BRIEF SUMMARY
The invention concerns a machine for the manufacture of containers, such as bottles, pots, or any other type of hollow body, by heat treating, then blow-molding, potentially combined with stretching, plastic preforms that have preliminarily undergone a suitable heat treatment.
The invention applies, in particular, to the manufacture of containers made of a thermoplastic material, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), copolyester, or an alloy or a mixture of several materials.
Conventional manufacturing machines designed to blow-mold preforms comprise at least the following: one preform heat-treating station in which the performs are heated to a temperature at which they can be reshaped during a blow-molding operation; a station which feeds the preforms to this treatment station; a blow-molding station comprising molds whose cavities incorporate the final outer shape of the container to be produced; and a station for preform transfer between the heat-treatment station and the blow-molding station.
In general, the preform must be stretch-formed at the time it is blow-molded. To this end, a stretch-forming device, such as an extension rod, which at this stage pushes backward the bottom of the preform in a controlled fashion, is linked to the blow-molding station.
The invention encompasses machines with and without stretch-forming devices. Accordingly, in the remainder of this description, the term "blow-molding" refers both to blow-molding alone and to blowing-molding/stretch-forming.
In one conventional type of machine produced by the Applicant, the supporting structure of the blow-molding station is a device mounted so as to rotate around a vertical axis of rotation. This device, termed a wheel or circular conveyor, supports at least two molds, each of which incorporates a mold cavity and is borne by a mold-carrier device and which are normally evenly spaced in relation to the axis of rotation.
In this type of machine, each mold comprises two half-molds jointed around an axis parallel to the axis of rotation of the circular conveyor. These half-molds are mounted in such a way that the molds open in the manner of a wallet toward the periphery of the blow-molding wheel.
In conventional practice, these machines allow high rates of production to be achieved. Thus, using a material such as PET, more than 1,000 containers per hour and per mold can be produced by stretch-forming/blow-molding. As an indication, the largest machines currently manufactured by the Applicant incorporate 40 molds.
In machines of this type, the heat-treatment station comprises holding devices, each of which is configured so as to receive and hold a preform firmly, but detachably, and which are arranged in series so as to constitute an endless-type mechanism. This endless mechanism may be formed either from another circular conveyor or in the form of an endless chain stretched between at least two drive pinions. Furthermore, the holding devices are preferably configured in such a way that the preforms can be heated with their opening (termed the "neck") pointing downward, in order to avoid any convection-induced deformation of this opening during heat treatment.
In addition, conventional machines are, preferably again, configured so that, following heat treatment, the preforms are reversed in such a way that the opening points upward, in order to avoid the situation in which, because of softening, they become deformed because of their own weight as they travel to the container blow-molding station. Depending on the type of machine, this reversing operation takes place in the heat-treatment or in the transfer station.
The operations entailing placement and removal of preforms on a rotating device are called "donning" and "undonning" in the language of those skilled in the art.
In a patent application filed by Applicant but as yet still unpublished, a major disadvantage of these machines is brought to light: i.e., they are in general constructed around mechanical structures (circular conveyor, motors, mol

REFERENCES:
patent: 3850566 (1974-11-01), Moore
patent: 4313720 (1982-02-01), Spurr
patent: 4391578 (1983-07-01), Schaar
patent: 4790741 (1988-12-01), Takakusaki et al.
patent: 5116217 (1992-05-01), Doudement et al.
patent: 5232717 (1993-08-01), Voss
patent: 5308233 (1994-05-01), Denis et al.
patent: 5683729 (1997-11-01), Valles

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